Question Your World: Can We Give Sight to the Blind?
Vision is one of the most useful aspects of life. Overtime the ability to see has guided evolution and allowed for many life forms to survive across the planet. Vision based injuries or degeneration can cause serious problems. While centuries of research have allowed us to understand the eye, we are still trying to figure out many ways to fix damaged vision. Recently scientists worked on an old question, can we give sight to the blind? Listen to this Question Your World radio report produced by the Science Museum of Virginia to find out.
First let's consider what an eye really is. Some of the earliest eye-like adaptations were eyespots. As the name suggests these were spots on creatures that were eye-like. Photoreceptors, the cells that detect light as visual data, have been evident in fossils of animals dating back to the Cambrian explosion about 570 million years back. Creatures with eyespots would later evolve into creatures with full on eyes, like us. After hundreds of millions of years of evolution we now have a world filled with millions upon millions of creatures that have eyes.
Dangerous amounts of light, genetic variables, and degeneration due to aging are a few ways that eyes can be damaged. Recently scientists explored this topic to see if there was a way around this big problem. Our eyes, like most other body parts, are comprised of a myriad of cells. The cascade of cells in the eye became the focal point of this recent study. When the outer layer of cells gets damaged, information stops being sent through the remaining layers. Visual information is sent down the chain of cellular connections and ultimately to the brain for processing. If an outer layer is damaged it can prevent the information from being passed down the chain and thus never getting the data to the brain.
For this particular study scientists looked at what would happen if you bypassed the nonfunctional cells and instead try to activate the layer of cells directly below the damaged ones. Using a genetic component they were able to get the second most outer layer to receive the light directly instead of receiving it as information being passed down through the outer layers. Once this genetic change was made to make these cells capable of detecting light their subjects started to react way better to visual testing. This process gave sight to subjects that were suffering from vision loss, but due to the damaged layers still sitting on top a lot of light is required. Regardless, scientists are hoping that this idea will at least allow for potential future patients to be able to see relatively well in the daytime.
Other applications for this could also involve better assisting patients that are suffering from epilepsy or other types of photoreceptor dysfunction. More testing is needed before moving on to human trials, but the initial test yielded some positive results.
So, which creatures did scientists give sight back to? Why, mice, of course! After successfully giving sight back to blind mice scientists feel confident that, if properly funded, they could even put Humpty Dumpty back together by 2025. Science, constantly trying to make the world a better place!